Although applicable to other electrical leads, the invention will be described with particular reference to solder tails on lead frames. Lead frames are commonly used to provide connections between electrical components inside the molded case of an electrical component package, and to provide electrically-conducting connectors extending from the interior to the exterior of the molded case. For example, an electric component and its lead frame may be at least partially enclosed in a dielectric case with leads therefrom extending outward through a wall of the case to the exterior. The external leads typically constitute so-called solder tails, which enable connection to an associated printed-circuit board or the like. Also typically, the solder tails initially extend directly outward from the molded case in a straight line, parallel to the plane of the lead frame, and are later bent sharply downwardly at right angles, after the molding operation, so their lower ends can be soldered in position on a printed circuit board, for example, in conventional manner.
It has been found that, in some cases, the interior of the case contains harmful contaminants traceable to contaminants produced during the lead-soldering operations. The present invention greatly reduces or eliminates such contamination of the interior of the case by contaminants generated outside the case.